The present invention is a method and system of automatic memory management (garbage collection). An application automatically marks up objects referenced from the "extended root set". At garbage collection, the system starts traversal from the marked-up objects. It can conduct accurate garbage collection in a non-GC language, such as C++. It provides a deterministic reclamation feature. An object and its resources are released immediately when the last reference is dropped. Application codes automatically become entirely GC-safe and interruptible. A concurrent collector can be pause-less and with predictable worst-case latency of micro-second level. Memory usage is efficient and the cost of reference counting is significantly reduced.